, 1887-09-07
HOW A DOG FOLLOWS TRAIL.


Scientific Investigator.
DR.. G. j. Romanes, by his careful OBJ
servations and happy concentrations, has
made himself the representative of the
growing science of comparative psychol-
ogy. DR.. Romanes has made an import
ant study on the method by which his
dog follows the scent of the master. The
observations were made on DIR. Romanes'
setter bitch, an animal very much at
tached to him. They were made on the
grounds adjoining his house, and a num-
Der Of precautions not easily described
were taken. Co.
When DR.. Romanes walks over the
ground with his hunting boots on, the
dog follows the scent with the greatest
readiness. If she is put to the track of a
stranger she pays no attention to it. The
dog was led into the room when prepara-
tons were going on for an outing, but
instead of DR.. Romanes going out, the
gamekeeper (whose scent she follows
next after that of DIR. Romanes) went;
when set free the animal at first followed
the track, but finding that her master
was not with the gamekeeper, returned.
The next experiment was a very in
genious one. Twelve men walked in In
dian file, so hat they all trod the same
footsteps, thus producing a conglomerate
of olfactory impressions. DIR. Romanes
headed the company, SO that the a of
his steps should be most obliterated; and,
aftor walking thus 200 yards, the first six
men walked in one direction, the last six
in another. The dog quickly ran along
the route followed by the twelve, over
shot the point of division, but soon re-
turned and followed the direction taken
by the six headed by DIR. Romanes.
A number of experiments were made
to ascertain what part of DIR. Romanes'
person or of his apparel gave the clew to
the animal. 1t was suspected to be the
hunting boots, and this proved correct.
A stranger put on these boots, and the
dog eagerly followed the scent; and, con-
trariwise, when DIR. Romanes put on the
strangers boots the animal was indiffer-
emit TO his track. Further experiments
were made to locate the source of the
scent in the boots. The dog did not fol-
low the scent of a stranger walking in
bare feet. When DIR. Romanes walked
in bare feet the dog followed the trace,
but less eagerly than usual, and with
much hesitation. Again, the animal did
not follow DIR. Romanes when he put on
new shooting boots. Next a single sheet
Of brown paper was glued to the soles of
his usual hunting boots. The dog did
not catch the trail until he came to a
place where, as DR.. Romanes had previ-
ously noted, a few square millimetres of
the paper had come off. When her
master walked in new cotton socks, the
trail was lazily followed, and o given
uN With wooden socks worn all day
thtresult was the same.
DIR. Romanes next walked fifty yards
in shooting boots; then 300 yards in his
stocking soles, carrying his boots; then
300 i'm his bare feet. The animal caught
the scent and followed it unhesitatingly
through the whole distance, though the
trace left by stockings or bare feet alone
was not sufficient to guide the animal.
The next was a modification of the last.
DIR. Romanes and a stranger entered q
carriage and drove for several hundred
yards. The former, in his hunting boots,
then alighted and walked fifty yards,
whereupon he re-entered the carriage,
and the stranger walked the next 200
yards; the dog, when shown the track,
ran the whole 800 yards without pausing.
The experiment was repeated with an
other stranger with the same result.
To test the power which the dog had of
selecting the distinctive odor accompany
ing her master from other odors. DIR.
Romanes soaked his hunting boots in
aniseseed oil. The odor was SO strong
that q friend could follow the track an
hour later by the odor Of the oil; yet the
dog was not confused except that she
hesitated about the first few steps, but
then pursued as usual.
The next test was directed toward as
certaining whether the animal could dis
tinguish her master by doors em~anating
from other portions of his person. DIR.
Romanes, after pursuing a zigzag our
Just trodden over by a number of foot
steps, hid behind a wall, with his eyes
just visible. The animal went at once to
the hiding place. Again, he hid in a
ditch, with only the top of his mead visi-
BILE. At 200 yards the dog detected her
master, and went to him directly.
From these tests DIR. Romanes con-
cludes that the dog distinguishes him
from all others by the odor of his boots,
and does not distinguish him in his naked
feet. Thu odor is probably emitted by the
feet, but must be mixed with that of shoe
leather TO be of service to the dog. This
is doubtless a matter of education; had
the dog been used 10 following her master
when without shoes, the amin : would
have learned to follow him The
characteristic odor cannot c a
sheet of brown paper, but u I, ,uars
millimeters of surface is sufficient 10 give
the dog the clew. The animal is ready to
be guided by inference as well as by per-
ception, but the inference is instantaneous.
Lastly, not only the feet through the
boots, but the whole body, emits an odor
that the dog can distinguish in a mass of
others. This odor is recognized 1t great
distances to windward, or in calm
weather in any direction; it is not over
powered by aniseseed oil or by the foot
prints of another. Science.